LYNN Ramsay impressed quite a few people with her first feature, “Ratcatcher,” a glum story of childhood in 1970s Glasgow.

Now comes the Scottish director’s second feature, “Morvern Callar.”

Based on a 1995 cult novel by Alan Warner, it is just as dark as “Ratcatcher” – and even more impressive.

Samantha Morton (“Sweet and Lowdown,” “Minority Report”) gives the finest performance of her career as Morvern Callar, a 21-year-old supermarket nobody in a small Scottish port who, just in time for Christmas, discovers her live-in boyfriend’s body on the kitchen floor, not far from the brightly lit Yule tree.

He has killed himself.

Seemingly unmoved, she opens the gifts he left for her – a jacket, a Walkman and a tape of music he compiled – and prepares to go out partying with her crude best friend, Lanna (a wonderful newcomer, Kathleen McDermott).

The body stays on the floor a few more days, as Morvern goes into her computer, takes the novel her boyfriend had written (“I wrote it for you,” he says in a suicide note), puts her name on it in place of his and mails it off to a publisher.

Stripping down to her panties, she butchers his body in the bathtub and buries it.

Then, with the money in her boyfriend’s bank account, she buys a booze-and-sex vacation in Spain for herself and Kathleen.

On the surface, Morvern appears to be amoral and heartless.

But Morton’s performance is so good, you end up feeling sorry for her character. So, too, she is able to make the minimal plot’s farfetched moments seem credible.

Morton deserves an Oscar nomination, but she is unlikely to get one. The movie is too dark and out of the mainstream to impress the conservative fogies who vote for the prizes.